Improvement in door-knob alarms



G. W. MOGOVERN. Boon-Knob Alarm.

No. 20l,l17. Patented March 12,1878.

jnven'zor' VI/neaoea JMO'QMO U TED ;S-TATES PA ENT O GEORGE w'gMcGovnRN,or: RICHMOND, VIRGINIA. I

' lMPRQ VEME NT 1N DOOR-KNOB ALARMSQ a specification forming pa t ofLetters Patent No. 201,117; dated man 12, 1878; application filed. 1

3 March1, 1878.-

To all whom it may concern;

ERN, of Richmond, inthe countyof Henrico .and State of Virginia, haveinvented .certain new and useful Improvements in Alarm-Knobs and I ddherebyde'clare that the following is a fullf'clear, andexactdesci-iption thereof, which "wil enable others skilled'in theartto'which it appertains to make and use the same, reference beinghadtothe accompanying drawings, and t'o'lettersof reference marked thereon,which form a part of this specification.

,Figure 1 is a perspective view of a door-lock having attached theretomy improved alarm. Fig. 2 is an elevation of the mechanism for soundingthe alarm, the bell 'being removed and Fig. 3 is a horizontal section.

Similar letters of reference indicate like partsof the invention.

The design of my invention is to furnish a compact, convenient, andeasily-applied mechanism whereby the opening of a door or efforts madeto open the same will cause an alarm to sound.

In the annexed drawing, A represents a door-lock of the usualconstruction, which is provided with a spring bolt or latch, that iswithdrawn from engagement with a keeper that is secured to or upon thedoor-jamb by means of a spindle, B, which passes through said lock anddoor, and upon the outer side of the latter has a knob, G, of ordinaryform. The projecting portion of the inner end of said spindle B, uponthe inner side of the door, is round, and upon the same is journaled asleeve, D,which extends about two-thirds the distance from the lock A tothe outer end of said spindle, and is held in longitudinal positionthereon by means of a collar, E, that is secured to or upon said spindleby a set-screw, 6. Upon the inner end of the collar E is provided aradial flange, e, which has the form, in front elevation, seen inFig.2,while immediately in rear of said flange is a plate, F, that isprovided with a rearwardextending hub, f, and is secured to or upon thesleeve D by means of a set-screw, f, which passes radially inwardthrough the hub. At or near its rear end the sleeve D is provided with aradial arm, 01, and between the same and the hub f of the plate F isjournaled the hub gof a bell-sh aped plate, Gr, which forms part of thecasing of my ,mechanism, and extends in a curye outward and forward-toorrne'ar said plate F. The hub g is connected-to or with thespindle B,bymeans-ofa screw, q, which passes radiallyinward through .said hub,

and has its.inner endcontained. within a corvided in sai d, spindle.

respondingly -threaded opening that is pro- Inorder that the sleeve I)mayhave freedom of 1notion,the opening d, through which passesthe;set-screw g, is elongated circumferentially a distance equal to themotion desired.

Upon the outer end-.- of the spindle Bis se- .curedabe1l, H, which is.placed with its concave side inward, and has substantially the samedimensions and shape as the casing G, the

result being the formation of a knob that is substantially the same insize and shape as those ordinarily used.

Pivoted to or upon each end of the plate F is a disk, I, which iscircular, except at one point, where are provided two gear-teeth, i and'i, that, when said disk occupies its normal position, extend inward anddownward. From the lower edge of each disk I extends downward and inwardin a curve a rod, is, to or upon the end of which is secured a hammer,K, that, by a partial rotation of said disk upon its pivotal bearing,may be caused to impinge upon the inner side of the bell H, near itsedge, and sound an alarm. Said disk and hammer are held in their normalpositions by means of springs, which, while arranged to yield so as topermit said hammer to move in either direction from such normalposition, will promptly return to the latter when the moving cause hasceased to operate.

Attached to the plate F is rod m, extending through the casing Gr, whichallows said plate to be withdrawn a suflicient distance to throw it outof line with the disks I, thereby allowing the knob O to be operatedwithout causing the alarm to be sounded.

The ends of the flanged plate 0 are formed upon the line of a circle, ofwhich the spindle B is the center, and within each of said ends, at ornear its lower corner, are out two notches, between which is left atooth, e, that corresponds to, and is capable of engagement with, theteeth 1' of the bell-hammer disk I.

As the parts are arranged, it will be seen that the casing-plate G,bellH, and flange-plate e are all connected with, and must movesimultaneous with, the spindle B, while the plate F may, by securing theouter end of the arm 61 of the sleeve D to or upon the door, beprevented from moving with said parts. If, now, the spindleB is turnedin either direction, the tooth e at the end of the flange e, which movesupward, will engage with and partially turn the contiguous disk I, so asto withdraw the hammer K from the bell H and when said flange .haspassed through about one-half its motion, said disk will be released,and, by the operation of its spring, said hammer will be caused tostrike against the bell. When the spindle B is released, thespring-latch of the lock returns it to its normal position, and causeseach of the bell-hammer disks to be engaged with the flange epreparatory to a new movement.

It isintended to leave the bell Huncovered, so as to cause the soundthereon of the hammer to be deadened by the hand of the person who opensthe door from the inside; but,

if desired, said bell may be contained within a casing, which willenable it to ring with the same freedom whether the lock is operatedfrom within or without.

I do not claim, broadly, in combination with an alarm which is containedwithin the knob of a door, a bell that forms part of such knob,

and has its sound mufiled when said knob is grasped by the hand, as suchaclaim is now the subject of an application filed by me, and now pendingbefore the Office; but

What I do claim as new and. useful, and desire to secure by LettersPatent, is

1. The combination of the spindle B, the sleeve D,the collar E, havingthe radial flange e and teeth 6, the .plate F, the pivoted disks I,provided with peripheral teeth 2', and having attached thereto thebell-hammers K and springs for returning said hammers to their normalpositions, substantially as and for the purpose shown.

2. The hereinbefore-described alarm, in which the sleeve D d, the-collarE e e", the flanged plate F, the casing-plate G, the bell H, the pivoteddisks I i, bell-hammers K, and springs to return said hammers to theirnormal positions are constructed, as shown, and combined with each otherand with the spindle B, in the manner and for the purpose substantiallyas set forth. v

In testimony that I claim the foregoing as my own I hereby affix mysignature in presence of two witnesses.

oEo. w. MGGOVERN.

Witnesses THEO. MUNGEN, D. ODONNOGHUE.

